Collapsible kayak apparatus and method

Abstract

An apparatus and method of use of a foldable watercraft and method of construction. The device comprises a collapsible boat hull constructed from a lightweight, low maintenance, and inexpensive material. The boat hull is frameless, folded and unfolded quickly, and is easy to transport and store.

That which is claimed is: 
     
         1 . A foldable kayak comprising:
 a foldable multichine hull comprising a cockpit of a size and dimension to fit a pilot;   a forward top deck extending from the cockpit to a bow of the kayak;   an aft top deck extending from the cockpit to a stern of the kayak;   a port hull side that extends from the bow of the kayak to the stern of the kayak comprising multiple chines, the chines extending from proximate the bow of the kayak to proximate the stern of the kayak, wherein the port hull side meets the forward and aft top decks defining a port side gunwale; and   a starboard hull side that extends from the bow of the kayak to the stern of the kayak comprising multiple chines, the chines extending from proximate the bow of the kayak to proximate the stern of the kayak, wherein the starboard hull side adjoins the forward and aft top decks defining a starboard side gunwale, wherein the port hull side and the starboard hull side meet underside the kayak to define a keel that runs from the bow of the kayak to the stern of the kayak.   
     
     
         2 . The invention of  claim 1  further comprising:
 a foldable insert of a size and dimension to fit inside the cockpit, comprising a floor thwart that runs from proximate the bow of the kayak to proximate the stern of the kayak that substantially defines a kayak floor; 
 a seat bottom defined by a second panel fixedly attached to the foldable insert, the second panel comprising a hinged flap that defines a seat back; and 
 a second multi-crease flap of the second panel hingedly extending from the first flap, the second flap that engages at least one interior wall of the cockpit defining an aft bulkhead. 
 
     
     
         3 . The invention of  claim 1  further comprising a cockpit coaming that extends from the aft deck proximate a border where the aft deck meets the cockpit. 
     
     
         4 . The invention of  claim 1 , further comprising:
 a first V-shaped center crease on the port hull side having a first bisecting crease beginning at the apex of the first V-shaped center crease and ending at the port side gunwale;   a plurality of fasteners on the exterior side of the port hull side that accommodate a first strap, wherein the first strap pulls the first V-shaped center crease closed upon itself, pinching the port hull side on itself to create a rocker in the keel and aiding in the structural integrity of the kayak;   a second V-shaped center crease on the starboard hull side having a second bisecting crease beginning at the apex of the second V-shaped center crease and ending at the starboard side gunwale; and   a plurality of fasteners on the exterior side of the starboard hull side that accommodate a second strap, wherein the second strap pulls the second V-shaped center crease closed upon itself, pinching the starboard hull side on itself to create a rocker in the keel and aiding structural integrity of the kayak.   
     
     
         5 . The invention of  claim 1 , wherein the foldable hull comprises a single sheet of plastic. 
     
     
         6 . The invention of  claim 5 , wherein the sheet of plastic is comprised of polypropylene twinwall plastic sheet. 
     
     
         7 . The invention of  claim 6 , wherein:
 the keel, proximate the bow of the kayak, is heat sealed forming a water-tight forward stem seal and foldable hinge; and   the keel, proximate the stern of the kayak, is heat sealed forming a water-tight aft stem seal and foldable hinge.   
     
     
         8 . The invention of  claim 6 , comprising:
 a center crease traversing the long axis of the plastic sheet, the center crease forming the kayak keel when folded;   a plurality of chine creases mirrored on each side of the center crease, the chine creases forming the multichine hull sides when folded;   a bow crease perpendicular to the center crease situated between the bow edge of the plastic sheet and the center of the plastic sheet, used to fold the kayak upon itself; and   a stern crease perpendicular to the center crease situated between the stern edge of the plastic sheet and the center of the plastic sheet, used to fold the kayak upon itself.   
     
     
         9 . The invention of  claim 8 , wherein:
 a plurality of first angled cuts emanate from a forward point on the keel, the first angled cuts having a size and dimension to remove material from the plastic sheet defining the edges that fold into the forward stem; and   a plurality of second angled cuts emanate from an aft point on the keel, the second angled cuts having a size and dimension to remove material from the plastic sheet defining the edges that fold into the aft stem.   
     
     
         10 . The method of unfolding a foldable kayak comprising the steps of:
 unclipping a strap that maintains the kayak in a folded state;   unfolding the forward end of the kayak along a forward crease;   unfolding the aft end of the kayak along a stern crease; and   spreading open the cockpit of the kayak.   
     
     
         11 . The method of  claim 10 , further comprising the step of tightening straps to maintain the kayak in an unfolded state. 
     
     
         12 . The method of  claim 10 , further comprising the step of inserting a foldable insert that defines a floor panel into a cockpit aperture. 
     
     
         13 . The method of  claim 12 , wherein the foldable insert comprises a seat. 
     
     
         14 . The method of sealing seams of a kayak made from polypropylene twinwall plastic sheet comprising the steps of:
 (a) creasing a first sheet having a first side and a second side with a die creating a first crease and first indentation on the first side;   (b) creasing a second sheet having a first side and a second side with a die creating a second crease and second indentation on the first side;   (c) orienting the first indentation of the first side of the first sheet opposite the second indentation of the first side of the second sheet forming a small substantially symmetrical inter-sheet cavity;   (d) clamping against the second side of the first sheet and the second side second sheet along the crease lines, creating a crease junction, and causing the inter-sheet cavity to collapse and the sheets to flare outwardly and opposedly deflect;   (e) heating the crease junction between the sheets, on the first sides of both sheets, from the direction where the sheets outwardly flare and opposedly deflect, also heating the first side of the first sheet proximate the first crease and the first side of the second sheet proximate the second crease;   (f) clamping the heated sheets using a substantially flat clamping surface; and   (g) fusing the heated sheets together forming a water-tight junction and hinged seam.